GB1574404A - Composite textile and method for making the same - Google Patents

Description

PATENT SPECIFICATION ( 11) 1574404

( 21) Application No 48441/76 ( 22) Filed 19 Nov 1976 ( 31) Convention Application No634 013 ( 19) ( 32) Filed 21 Nov 1975 in + ( 33) United States of America (US) k ( 44) Complete Specification published 3 Sept 1980 ( 51) INT CL 3 CO 8 L 3/02; A 47 G 27/02; CO 8 L 9/00//B 32 B 5/26, 7/12, 9/02, 25/02 ( 52) Index at acceptance C 3 M 118 120 121 133 134 153 154 163 200 C B 2 E 1703 400 S 467 CT 474 S 484 T 489 S 490 T M B 5 N 0526 0712 0902 2502 C 3 U 10 D 12 B 1 B 1 12 B 2 A 12 B 2 C 2 AX ( 72) Inventors DOUGLAS, J LADISH CLAIRE D Le CLAIRE, JOHN J MARTIN, EMIL G SAMMAK ( 54) COMPLETE TEXTILE AND METHOD FOR MAKING THE SAME ( 71) We, REICHHOLD CHEMICALS, INC, a Corporation organised 5 under the laws of the State of Delaware, United States of America, of RCI Building, 525 North Broadway, White Plains, New York 10603, United States of America, do hereby declare the invention for which we pray that a patent may be granted to us and the method by which it is to be performed to be particularly

described in and by the following statement: 10

This invention relates to composite textiles, such as tufted carpets, having improved strength and durability and to a method of forming such composite textiles.

Aqueous latices of polymers are used extensively for the manufacture of tufted carpets, the latices usually being mixed with major proportions of mineral fillers 15 Thse aqueous compositions are applied to the back of a fabric into which tufts of yarn have been inserted; this fabric is known as the primary fabric, and is conventionally a woven jute fabric, a needled or spun-bonded non-woven polypropylene fabric, or a fabric formed from woven polypropylene ribbon, although other fabrics may be used 20 After the application to the fabric of the aqueous composition for example, by spreading or spraying, the fabric carrying a layer of the aqueous latex composition is dried, usually in a forced-draught hot air oven at an elevated temperature The latex composition is thus converted into a layer consisting of mineral filler bound by polymer This layer serves to give weight and dimensional stability to the carpet 25 Even more important, the dry, polymer-bound layer binds the tufts of yarn to the primary fabric into which they have been inserted, and by surrounding the base of the yarns which comprise the tufts also improves the resistance to breaking and separation of the individual filaments which form the yarns.

Sometimes a layer of frothed latex which usually also contains mineral filler is 30 applied to the fabric after application of a precoat layer of a latex composition as described previously, in order to obtain a carpet with an elastomeric or at least a flexible foam backing In this event the precoat is usually only partially dried before application of the layer of wet latex froth, and drying is completed at the same time.

The purposes for which such a pre-coat is applied are, inter alia, to bind the tufts, to 35 provide extra weight to the carpet and to provide a level base for foam backing.

Yet another construction which is important in tufted carpet manufacture is so so-called secondary backing in which a layer of secondary fabric is laminated to the primary fabric This secondary fabric is again woven jute or a woven or non-woven polypropylene fabric, and may be the same as or different from the primary fabric 40 In this construction, a layer of a similar latex composition is applied as previously described to the back of the fabric; the secondary fabric is then united with the wet adhesive, and the carpet conveyed through a drying oven In this type of construction the function of the latex composition is to secure a good bond between the primary and secondary fabrics, before during and after drying; in 45 addition to securing anchoring of the tufts in the primary fabric.

2 1,574,404 2 According to one aspect of the present invention there is provided a composite textile comprising a fabric substrate having adhered thereto a dried latex composition containing from 10 to 70 phrs of gelatinized starch distributed substantially uniformly throughout the thickness of the composition.

According to another aspect of the present invention there is provided a 5 method of forming a composite textile, wherein a composition comprising a mixture of an aqueous latex and from 10 to 70 phrs granular starch is applied to a fabric substrate to form a composite textile, and wherein said composite textile is heated under conditions whereby at least a substantial proportion of the starch is gelatinized substantially uniformly throughout the thickness of the composition 10 whereafter the composite textile is dried.

The latex-starch composition used in the present method may be applied in the manufacture of tufted carpets and other composite textile such as woven carpets; upholstery fabrics; curtaining fabrics; needlefelt carpets; lightweight laminated fabrics including apparel fabrics; and non-woven fabrics, for such purpose as 15 providing improved weight, handle, drape or opacity to the composition textile, in addition to improved strength and durability and dimensional stability.

The term "strength and durability" of the composite textile refers to its performance under conditions of practical use when the textile is subjected to a variety of disruptive forces The contribution to strength and durability made by 20 the latex-starch composition used in the present method can be assessed in different ways according to the end use; test methods and data from such tests are exemplified and described later in this Specification.

The rheological behaviour of a latex composition is quite important with regard to the properties that the composition will impart to a composite textile For 25 instance, if the viscosity of the composition is excessive, the latex will not penetrate sufficiently into the textile to provide the desired binding properties On the other hand, if the viscosity of the latex is too low, excessive penetration of the latex composition through the textile takes place such that the latex does not provide the desired binding properties 30 For example a latex composition which is to be utilized for forming a composite textile which comprises a secondary backing must develop a good bond as early in the drying and curing process as possible, in order to minimize displacement of the secondary backing through mechanical movement This property is generally referred to in the textile art as "early bonding" The 35 rheological behaviour of the latex composition is specially important in secondary backing processes.

A wide variety of aqueous copolymer latices may be used to prepare the latex compositions used to make the present composite textiles, for example natural rubber latex and synthetic butadiene copolymer latices Preferred latices are 40 butadiene/styrene/unsaturated carboxylic acid polymer latices prepared by emulsion polymerization, in which the polymer is elastomeric or flexible However, a wide variety of other monomers may be copolymerised in admixture with butadiene in emulsion in order to prepare elastomeric or flexible copolymer latices useful in the compositions employed in the present method, for example 45 acrylonitrile; methacrylonitrile; alkyl esters of acrylic and methacrylic acids containing up to 8 carbon atoms such as methyl methacrylate, ethyl and butyl acrylates; acrylamide; N-methylolacrylamide; vinylidene chloride; and alphamethyl styrene.

It will be appreciated that the flexibility of the copolymer, hence the handle of so the resulting composite textile, can be adjusted in various ways, such as by adjusting the composition of the copolymer, or by blending latices of copolymer of different compositions in order to obtain the desired handle.

Latex compositions used for laminating textiles generally contain large amounts of finely divided inorganic filler such as whiting (Ca CO 3), barytes, 55 alumina, pigments and the like These materials are added to impart certain secondary properties such as opacity, fire retardance, stiffness and colour.

In addition to the above-referred primary functional components, latex compositions may also contain various conventional additional components such as antioxidants, defoamers, plasticizers, bactericides, emulsifiers, thickeners, 60 dispersants and the like.

Many different types of drying plant are in industrial use for producing textiles In the commercial manufacture of composite textiles, it is generally the practice to dry to the desired moisture level in the shortest possible period so that the maximum output of the plant can be achieved The driers may be operated at 65 air temperatures of from 150 to 2600 C.

When a composite textile formed by the utilization of a latex-starch composition is subjected to drying conditions commonly used in the production of composite textiles, the starch will not gelatinize or swell uniformly to impart improved strength and durability to the composite even through gelatinization 5 temperatures for starch are in the range of from about 550 to 700, depending upon the particular starch utilized This failure is due to the rapid removal of water at the surface of the composite by the high velocity heated air, at temperatures substantially below the air temperature of the oven Furthermore, the evaporative cooling effect tends to maintain the latex-starch composition at a temperature 10 substantially below the air temperature of the dryer and may be below the temperature where any substantial degree of gelatinization occurs The temperature of the composite textile will rise rapidly when sufficient water is vaporized and then will be above that normally required for gelatinization of the starch However, at this stage there is generally an insufficient amount of moisture is present to effect gelatinization.

In a typical carpet drier such as is in common industrial use, the textile which has been coated with a latex composition is passed on stenters through a drying.

oven consisting of a number of drying chambers into which air, heated to a temperature of from 150 to 2600 C is introduced from nozzles via manifolds These 20 nozzles are disposed in the drying chambers in rows which are at right angles to the direction of motion of the carpet, and are located above and below the surfaces of the textile.

A drier such as is briefly described above may be modified for carrying out the present method by providing a first drying chamber containing a reduced number 25 of hot air nozzles followed by horizontal plates between which the coated textile is passed In this zone the temperature of the textile is raised while the rate of evaporation of moisture from the composite is reduced, in order to provide sufficient temperature and time to allow the starch to gelatinize The textile subsequently passes through unmodified drying chambers in order to complete 30 drying.

It should be appreciated that other modifications may be made to a typical carpet dryer which would produce similar results For instance, a wicking pad containing water may be utilized as a replacement for or in conjunction with the spaced plates or steam may be sprayed onto the surfaces of the composite textile In 35 fact, any additional means may be utilized in a dryer which provides conditions conducive to the substantially complete gelatinization of the starch.

If the starch is not gelatinized, it merely acts as an extender or filler and does not impart any strength to the composite textile In an intermediate stage with respect to the starch particles, the larger particles are gelatinized and thus swollen 40 In the case of a tufted carpet with secondary backing, the starch particles may be gelatinized to a greater degree next to the primary backing hence, greater strength is imparted to that portion of a composite textile This will be manifested by improved tuft lock If starch particles are completely gelatinized throughout the composite, the improved strength of the entire composite will be manifested by 45 improved tuft lock and strip-back.

As discussed previously, latex compositions utilized for forming composite textiles generally contain inorganic fillers While fillers may impart properties such as opacity, fire retardance, stiffness and colour, they will generally decrease the strength of a composite textile 50 It is possible to show by means of photomicrographs and electron micrographs of cross-sections of latex-starch-mineral filler compositions which have been heated and dried under different conditions that, when the conditions are such as to ensure gelatinization of the starch, the particles of filler (whiting or calcium carbonate, for example) are smoothly coated with starch, whereas, in the event of 55 insufficient gelatinization, the filler particles are not continuously coated Thus, when gelatinization is allowed to occur, the surfaces of the filler, which is a polar substance, are thoroughly coated and bound by the polar starch and the strength and durability of the dried composite are thereby improved.

We have found that when a composite textile coated with latex containing 60 granular starch particles is heated and dried to a temperature and under conditions to cause the starch particles to swell substantially uniformly throughout the thickness of the composite, to at least about two and preferably 4 to 10 times their original volume, the strength and durability of the resulting composite textile is significantly improved The coating on the composite textile can be stained with 65 1,574,404 iodine after the latex-starch composition has been heated and dried and the starch granules can be observed as black specks in an optical microscope It is believed that doubling the diameter of the granules destroys the crystallinity, in other words an eight fold increase in volume totally destroys the original crystallinity However an intermediate degree of gelatinization confers some reinforcement 5 It will therefore be appreciated that the starch-latex compositions used in the present method contain starch predominantly in the form of granular particles before the compositions are heated above ambient temperatures and dried in order to produce the present composite textiles, and that during said heating and drying the starch particles gelatinise and swell substantially informly throughout the 10 thickness of the composite to at least about two and preferably to between 4 and 10 times their original volume.

In the following part of the description and Examples, phr-refers to parts added per 100 parts latex dry basis; phs-refers to parts added per 100 parts starch dry basis; 15 phrs-refers to parts added per 100 parts of latex plus starch dry basis.

While, as discussed above, it is somewhat difficult to achieve substantially complete gelatinization of starch in a latex-starch composite under commonly used drying conditions, various agents may be used to lower the gelatinization temperature of the starch These agents will hereinafter be referred to as starch 20 sensitizers Starch sensitizers are well known in the art and include, for example, the following: alkali metal hydroxides, barium hydroxide, tetramethylammonium hydroxide, benzyltrimethylammonium hydroxide, ethylene diamine, hydrazine hydrate, dimethyl sulphoxide, calcium chloride, sodium silicate, sodium, potassium or ammonium thiocyanate, borax, quaternary fatty amines, sodium xylene 25 sulphonate, lithium bromide, guanidinium chloride, dicyandiamide, sodium lauryl sulphate and "Deriphat" 160 C ("Deriphat" is a registered Trade Mark for a product of General Mills; disodium salt of N-lauryl beta iminodipropionate-an amphoteric emulsifier of the class of N-long chain alkyl substituted Palanine).

The particular sensitizer and the amount thereof used will vary depending 30 upon a number of factors such as the amount of starch present, the manner in which the sensitizer is added, the conditions under which the composite textile is heated or dried, the compatibility of the sensitizer with the latex, the particular additives or modifiers contained in the latex formulation and the desired viscosity.

of the latex formulation 35 The rheology of the latex-starch composition is quite important For instance, if the viscosity thereof is too low or high it cannot be handled properly in a commercial textile operation Starch sensitizers tend to increase the viscosity of latex-starch formulations since, under certain conditions, they will cause a portion of the starch to dissolve and also at sufficiently high concentration may gelatinize 40 the starch at ambient temperatures When this occurs the latex-starch composition will be substantially impossible to handle in a commercial operation.

The preferred sensitizer is sodium hydroxide because of its high efficiency at low concentrations and its compatability with a wide variety of latex compositions.

In the case of sodium hydroxide, it is preferred to utilize from 1 to 10 parts thereof 45 per 100 phs The preferred sensitizer is a mixture of a borate and sodium hydroxide.

In the case of a mixture of borax and sodium hydroxide, the preferred proportions are from 1 phs to 20 phs of borax and 1 phs to 8 phs of sodium hydroxide On an equal weight basis, sodium hydroxide will sensitize starch to a lower gelatinization temperature than, for instance, borax Thus, the finding that a mixture of boarx and 50 sodium hydroxide imparts the greatest degree of improvement in strength and durability of the composite textile is surprising It is believed that since borax complexes with the hydroxyl groups of the starch it imparts superior film characteristics to the resultant dried composite.

The order of addition of the borax and sodium hydroxide to the latexstarch 55 composition apparently plays an important role in the degree to which the starch will impart strength and durability to the dried composite textile If the sodium hydroxide is added prior to the borax in preparing the latex-starch composition, the composite textile has greater strength and durability than if the reverse order of addition is used 60 While the amount of fillers, i e, whiting (Ca CO 3), barytes, alumina, clay, pigments and the like, utilized in the present invention may vary over a relatively wide range, for example, up to 800 phrs, in general, amounts from 150 to 600 phrs will be present The preferred amount of filler is in the range of from 350 to 500 phrs 65 1.574404 The proportion of starch present in the latex-starch composition may also vary _ over a relatively wide range depending upon a number of factors such as the type of starch used, the type and amount of sensitizer used, the amount and kind of inert filler present, the particular latex, and the desired properties of the final composite textile The preferred proportion of starch is from 10 to 40 phrs The greatest S improvement in the strength and durability of the textile composite is observed by use of a proportion of starch within this range while maintaining the desirable properties of the latex polymer in the composite textile, such as flexibility, resilience and softness of hand, but the proportion of starch may be as high as 70 phrs without loss of strength and durability 10 The starch to be used in the composite textiles and the latex-starch compositions must be one which does not result in excessively high viscosity when mixed with the aqueous latex and inorganic filler Both root and cereal starches may be used so long as they are granular and are essentially cold waterinsoluble.

The starch may be either unmodified or modified as by oxidation, acid treatment, 15 ethoxylation and the like providing that the crystal structure of the native granules is present and that when heated the starch gelatinizes The granular starches may be derived from corn, potato, tapioca, wheat, rice, waxy sorghum and waxy maize, for example Dextrins may be employed so long as their molecular weight has not been lowered to such an extent as substantially to destroy crystallinity or to 20 increase cold water solubility above about 30 percent (preferably no more than about 20 percent) It is, however, preferred to employ a starch which has been modified by acid treatment or by oxidation These methods are well known in the art.

In order more clearly to describe the nature of the present invention, specific 25 Examples will hereinafter be described in greater detail.

In the following examples, the terms "carpet laminates", "fabric laminates" and "precoated carpets" have the following meaning.

Carpet Laminates A level loop, 3 ply acrylic 30 oz /sq yd, carpet with a woven polypropylene 30 primary is coated with a latex-composition and a jute 8 oz /sq yd secondary backing is laminated to the carpet The laminate is dried, cooled and cut into strips 3 inches wide and T-Peel Bond Strength (also known as "stripback") is determined according to ASTM test procedure D-2724 Results are reported in pounds per 3 inch strip 35 Fabric Laminates Canvas or cotton ticking is coated with latex composition and laminated by folding the fabric so that the latex coated sides are joined together The laminate is dried, cooled and cut into strips 1 inch wide and T-Peel Bond Strength is determined according to ASTM test procedure D-2724 Results are reported in 40 pounds per one inch strip.

Precoated Carpets A carpet is prepared as noted above for "Carpet Laminates", except that a secondary jute backing is not applied Pile anchor (also known as "tuft lock") is determined by ASTM procedure D-1335 Results are reported in the pounds 45 required to pull out one tuft.

Viscosity Viscosity determinations were made with a Brookfield Synchro-lectric

Viscometer with number 5 spindle at a speed of 20 RPM.

Example 1 50

A latex-starch composition was prepared containing 80 phrs latex, 20 phrs starch, 400 phrs whiting and sufficient water to obtain a total solids concentration of 70 percent; thus for each 20 g starch there was 214 3 g of water This composition was coated on a carpet as a primary backing and a secondary jute backing was adhered thereto Weighed samples of the composite were placed in a 55 laboratory circulating air oven maintained at a temperature of 1210 C and at various intervals samples were removed from the oven and weighed to determine their residual moisture.

The internal temperature of the composite was measured at one minute S 1.574,404 intervals by means of an iron-constantan thermocouple implanted in the latexstarch portion-of the composite.

The internal temperature and residuel moisture values were plotted vs time in the form of graphs.

If it is assumed that the minimum amount of water which must be present to 5 gelatinize the starch is equal to the weight of the starch, then about 9 3 percent of the original water must be present at some temperature when gelatinization of the starch takes place In the absence of starch sensitizers, independent experiments show that this is in the range of 670 to 720 C In the case where a starchsensitizer system comprising 4 phs sodium hydroxide, 14 phs borax, and 20 phs urea is 10 present, gelatinization of the starch would occur in the range of 620 to 670 C.

The graphs obtained showed that in the absence of any starch sensitizer, under the conditions of the experiment the internal temperature of 670 C which is the minimum for gelatinization was reached when the moisture content of the composite had fallen to less than 9 3 %, hence gelatinization would not occur On 15 the other hand, were the temperature required for gelatinization to be reduced to a minimum of 620 C by means of the starch sensitizers referred to, the starch would be gelatinized within the same period of heating.

Thus under practical drying conditions a difference between temperatures required for gelatinization of only a few degrees can determine whether 20 gelatinization of the starch in the latex-starch composition occurs at all, accordingly also the strength and durability of the composite textile.

Example 2.

This Example illustrates the preparation of a composite textile utilizing a latexstarch composition, and demonstrates the improved strength and durability 25 imparted to the laminate by the starch in the presence of added starch sensitizer.

A carboxylated butadiene-styrene latex was prepared by emulsion polymerization methods well known in the art to achieve a monomer conversion of at least 90 % After the completion of the polymerization, the latex was stripped and concentrated to a polymer solids level of 50 to 55 % by weight 30 Carpet laminates were coated with 32 oz /sq yd (dry weight) of the latex composition set forth in Table 1 below and dried in a circulating air oven for 15 minutes at an air temperature of 1400 C The bond strengths of the laminates were determined and are reported in Table 1.

TABLE 1

Effect of Latex-Starch on strength and durability of Composite Textiles Composition Sensitizer (phs) Bond Latex Starch Strength Composite (phrs) (phrs) Na OH Borax ( 1 b 6/3 in) 1 100 28 0 2 100 20 1 5 3 100 4 9 8 4 90 10 4 9 43 0 Water and polyacrylate thickener were added to obtain 37 % solids and a viscosity of 13 to 14,000 cps.

Acid modified starch (Clinton 155-B manufactured by Clinton Corn Processing Company) As shown in the above table, Composite 4 had increased strength and durability indicating that the starch was substantially gelatinized.

1,574,404 Example 3.

This Example illustrates the effect of various proportions of starch sensitizers on the strength and durability of composite textiles.

Carpet laminates were prepared as described in Example 1 using the latexstarch composition set forth in Table II below:

TABLE II

Effect of Proportions of Starch Sensitizers on strength and durability of Composite Textiles Composition Latex Starch Composite (phrs) (phrs) Sensitizer (phs) Bond Strength Na OH Borax Urea (lbs /3 in) 0 16 11.3 13.5 17.5 15.7 17.9 17.0 10.7 13.8 16.8 350 phrs of whiting and sufficient water and polyacrylate thickener were added to each sample to obtain 71 % total solids and a viscosity of 13 to 14, 000 cps.

Acid modified starch (Clinton 155-B manufactured by Clinton Corn Processing Company) The above table shows that, in general, the strength and durability of a composite textile is improved at increasing levels of sodium hydroxide and that, under the particular drying conditions utilized, in the absence of sodium hydroxide the desired strength is not obtained.

Example 4.

This Example illustrates the effect of pretreating composite textiles to increase the strength and durability thereof.

Carpet laminates were prepared as described in Example 2 and fabric laminates were prepared in a similar manner using in each case the latexstarch compositions set forth in Table III below One-half of the laminate samples were dried for 15 minutes in a circulating air oven at an air temperature of 140 C The other samples were subjected to a steam atmosphere for 15 minutes at 100 C in an autoclave and then dried in the same manner as the other samples The strength of the samples was determined and is shown in Table III below:

1,574,404 8 A 40 U TABLE III

Comparison of Laminate strength and durability Normal Drying vs Steaming Prior to Drying Compo si tion Latex (phrs) Starch (phrs) Borax (phs) Bond Strength Unsteamed Steamed Fabric Laminates Carpet Laminates Ibs /1 inch strip 3.8 3.5 3.2 3.6 4.0 4.7 Ibs-/3 inch strip 10.8 10.7 9.7 10.9 11.6 11.6 350 phrs whiting and sufficient water and polyacrylate thickener were added to each sample to obtain 71 % total solids and a viscosity of 13 to 14,000 cps.

Acid modified starch (Clinton 155-B manufactured by Clinton Corn Processing Company) It is seen from the above table that in all cases where the composites were steamed to ensure complete gelatinization of the starch, the strength of the resulting composites was improved.

Example 5.

This Example illustrates the effect of the period of pretreating composite textiles on the strength and durability of the resulting composite.

Fabric laminates were prepared with the latex-starch compositions set forth inTable IV The laminates were heated for 90 seconds in a circulating air oven at 1400 C and then were placed between two aluminium plates which were positioned in the oven At various periods the laminates were removed from between the plates and dried for 15 minutes in the oven The purpose of the plates was to reduce evaporation of moisture and thus provide sufficient water to ensure gelatinization of the starch The strength of each of the laminates was determined and is reported in Table IV below:

Composite 1.-574404 Q TABLE IV .0 Effect of Moisture Control During Early Stages of Drying on strength of Composite Textiles Bond Strength (lbs /in) Composition (Time Between Hot Plates) Latex Starch Na OH Borax 0 7 15 30 60 Composite (phrs) (phrs) (phs) (phs) Sec Sec Sec Sec Sec.

1 100 0 1 6 2 6 1 2 82 18 2 8 5 3 6 1 6 2 6 4 6 7 3 80 20 0 4 0 8 5 7 6 5 6 6 6 8 6 4 400 phrs whiting and sufficient water were added to each sample to obtain 71 % solids therein Polyacrylate thickener was also added to each composite to obtain therein a viscosity of 13 to 14,000 cps.

Acid modified starch (Clinton 155-B manufactured by Clinton Corn Processing Company) From the above table, it is seen that the composite textiles which contained starch had better strength than the samples which did not and also that the utilization of sodium hydroxide as the starch sensitizer resulted in improved strength in a shorter period 5 Example 6.

This Example illustrates the utilization of carboxylated acrylonitrile butadiene styrene and butyl acrylate-acrylonitrile latices for forming composite textiles.

Acrylonitrile butadiene styrene itaconic acid polymer ( 20/50/27 5/2 5) and butyl acrylate acrylonitrile methylolacrylamide polymer ( 85/15/5) latices were 10 prepared by emulsion polymerization techniques well known in the art.

Fabric laminates were prepared with the latex starch composition set forth in Table V and laminates pretreated for 30 seconds according to the procedure described in Example IV Other laminates were not treated but simply dried in a circulating air oven at 140 C for 15 minutes The strength of each of the laminates 15 was determined and is reported in Table V below:

1,574,404 TABLE V

Comparison of Laminate Cohesiveness Normal Drying vs Steaming Prior to Drying Latex Polymer Composite Latex Polymer (phrs) Starch (phrs) Borax (phs) AcrylonitrileButadiene Styrene 1 2 3 ButylacrylateAcrylonitrile 80 100 0 20 20 0 15 O 5.

80 0 20 20 0 0 10 0 15 0 0 2 Bond Strength 6.6 6 6 5 9 5 3 5 6 Pretreated (lbs /in) Bond Strength 6.4 5 4 5 4 5.6 4 8 4 4 Untreated (lbs /in) % Increase from Pretreatment 3 18 8 -0 6 14 15 400 phrs whiting, sufficient water, and polyacrylate thickener were added to each sample to obtain 71 % total solids and a viscosity of 13 to 14,000 cps.

Acid modified starch (Clinton 155-B manufactured by Clinton Corn Processing Company) It can be seen from the above table that in all cases where the composites were pretreated to provide sufficient moisture therein during heating so as to ensure substantially complete gelatinization of the starch, the strength of the resulting composite was improved.

Example 7.

This Example illustrates the interaction of starch with whiting to impart improved strength to composite textiles.

Laminates were prepared by coating fabric with about 16 oz /sq yd of the latex-starch compositions set forth in Table VI below Sufficient polyacrylate' thickener was added in each case to obtain a viscosity of 13 to 14,000 cps.

Sufficient water was added to obtain 71 % total solids One-half of the laminate samples were dried for 15 minutes in a circulating air oven at an air temperature of C, while the other samples were pretreated in accordance with the procedure described in Example 5 for 45 seconds and then dried for 15 minutes in the oven.

Urea (phs) Na OH (phs) 0 O 0 O 5.2 TABLE VI

Interaction of Starch with Filler Filler (phrs) Latex/Starch Na OH Borax (phrs) (phs) (phs) 300 350 400 450 500 Normal Oven Drying Bond Strength lbs /in.

100/0 8 4 7 7 6 6 6 1 5 8 80/20 4 4 6 9 6 1 5 5 5 4 4 8 60/40 1 5 1 5 5 3 5 0 4 6 4 2 4 3 40/60 0 67 0 67 4 3 3 8 3 5 3 5 3 1 Heated with Moisture Retained 45 sec Then Over Dried Bond Strength lbs /in.

100/0 8 2 7 3 6 3 5 7 4 4 80./20 4 4 8 3 7 5 6 8 6 3 5 6 60/40 1 5 1 5 7 7 6 6 6 4 62 5 9 40/60 0 67 0 67 7 3 6 8 7 1 6 3 5 8 % Change Due to Moist Heat 100/0 -2 -5 -5 -7 -24 80/20 + 20 + 23 + 25 + 17 + 17 60/40 + 44 + 32 + 39 + 48 + 37 40/60 + 70 + 79 + 103 + 80 + 87 1 phr Na OH 1 phr Borax Acid modified starch (Clinton 155-B manufactured by Clinton Corn Processing Company) The above table shows that when composites are subjected to conditions to ensure substantially complete gelatinization of starch, greatly increased strength resulted Also, it is seen that at whiting levels in the range of 350 to 500 phrs, the strength of the composite textiles which were subjected to conditions to ensure 5 complete gelatinization of the starch was greater than for the composite textiles which consisted entirely of latex at similar filler levels.

Example 8.

This Example illustrates the improved strength and durability of precoat carpets prepared with a latex-starch composition 10 A carboxylated butadiene-styrene latex was prepared by the method disclosed in Example 2, and water and 500 phrs whiting were added to obtain a solids level of 71 % The composition was thickened to 13 to 14,000 cps with polyacrylate thickener.

1,574,404 The backs of tufted carpets were coated with 22 oz /sq yd (dry basis) of the latex composition set forth in Table VII One set of the coated carpets was dried in a circulating air oven for 15 minutes at an air temperature of 1680 C, while the other set of coated carpets was pretreated by exposure to a stream atmosphere for 1 minute and then dried as the previous set The pile anchor values of the precoated 5 carpets were determined and are set forth in Table VII.

TABLE VII

Effect of Moisture Control During Early Stages of Drying On Strength and Durability of Precoat Carpet Pile Anchor (lbs /tuft) Latex Starch Na OH Borax Normal Drying Composite (phrs) (phrs) (phs) (phs) Pretreated Conditions 1 100 12 6 10 4 2 70 30 4 0 2 3 14 6 11 6 3 70 30 6 0 2 3 14 4 12 0 4 40 60 2 0 0 67 12 2 9 3 40 60 5 0 0 67 14 4 12 7 1 2 phr Na OH 1 0 phr Borax

Claims (1)

1. WHAT WE CLAIM IS:-

   1 A composite textile comprising a fabric substrate having adhered thereto a dried latex composition containing from 10 to 70 phrs of gelatinized starch 10 distributed substantially uniformly throughout the thickness of the composition.

   2 A composite textile as claimed in claim 1, wherein the composition contains from 10 to 40 phrs gelatinized starch dry basis.

   3 A composite textile as claimed in claim 1 or 2, wherein the composition contains a starch sensitizer for lowering the temperature at which gelatinization of 15 the starch occurred.

   4 A composite textile as claimed in claim 3, wherein the starch sensitizer is sodium hydroxide.

   A composite textile as claimed in claim 4, wherein the sodium hydroxide is present in an amount of 1 to 10 phs 20 6 A composite textile as claimed in claim 3, wherein the starch sensitizer comprises a mixture of a borate and sodium hydroxide.

   7 A composite textile as claimed in claim 6, wherein the starch sensitizer comprises from 1 to 20 phs borax and from l to 8 phs sodium hydroxide.

   8 A composite textile as claimed in any one of claims 1 to 7, wherein the 25 composition contains up to 800 phrs filler dry basis.

   9 A composite textile as claimed in any one of claims l to 8, wherein the composition contains from 150 to 600 phrs filler dry basis.

   A composite textile as claimed in any one of claims 1 to 9, wherein the composition contains from 350 to 500 phrs filler dry basis 30 11 A composite textile as claimed in any one of claims 1 to 10, wherein said fabric substrate constitutes a primary layer, and wherein a secondary layer is adhered to the primary layer by said latex composition.

   12 A method of forming a composite textile, wherein a composition comprising a mixture of an aqueous latex and from 10 to 70 phrs granular starch is applied to a 35 fabric substrate to form a composite textile, and wherein said composite textile is heated under conditions whereby at least a substantial proportion of the starch is gelatinized substantially uniformly throughout the thickness of the composition, whereafter the composite textile is dried.

   1,574,404 13 A method as claimed in claim 12, wherein the composition when dried, contains from 10 to 40 phrs starch dry basis.

   14 A method as claimed in claim 12 or 13, wherein the composition contains a starch sensitizer for lowering the gelatinization temperature of said granular starch.

   15 A method as claimed in claim 14,'wherein the starch sensitizer is sodium 5 hydroxide.

   16 A method as claimed in claim 15, wherein the sodium hydroxide is present in an amount of from 1 to 10 phs.

   17 A method as claimed in claim 14, wherein the starch sensitizer comprises a mixture of a borate and sodium hydroxide 10 18 A method as claimed in claim 17, wherein the starch sensitizer comprises from I phs to 20 phs borax and from 1 phs to a 8 phs sodium hydroxide.

   19 A method as claimed in claim 17 or 18, wherein the sodium hydroxide is incorporated into the composition prior to the incorporating of the borate.

   20 A method as claimed in any one of claims 12 to 19, wherein the 15 composition contains up to 800 phrs filler dry basis.

   21 A method as claimed in any one of claims 12 to 20, wherein the composition contains from 150 to 600 phrs filler dry basis.

   22 A method as claimed in any one of claims 12 to 21, wherein the composition contains from 350 to 500 phrs filler dry basis 20 23 A method as claimed in any one of claims 12 to 22, wherein the composite textile is heated at a temperature of from 55 to 700 C in a moistureladen atmosphere in order to gelatinize the starch.

   24 A composite textile in accordance with claim 1, substantially as hereinbefore described in any one of the foregoing Examples 25 A method of forming a composite textile in accordance with claim 12 substantially as hereinbefore described in any one of the foregoing Examples.

   TREGEAR, THIEMANN & BLEACH, Chartered Patent Agents, Enterprise House, Isambard Brunel Road, Portsmouth P 01 2 AN and 49/51, Bedford Row, London WC 1 V 6 RL.

   Printed for Her Majesty's Stationery Office by the Courier Press, Leamington Spa, 1980.

   Published by the Patent Office, 25 Southampton Buildings, London, WC 2 A l AY, from which copies may be obtained.

   1,574,404